Architecture for light emitting elements in a light field display

ABSTRACT

The disclosure describes various aspects of an architecture for light emitting elements in a light field display. In an aspect, a light field display can include multiple picture elements (e.g., super-raxels), where each picture element includes multiple sub-picture elements monolithically integrated on a same semiconductor substrate. Each sub-picture element has a respective light steering optical element and includes an array of light emitting elements (e.g., sub-raxels) that produce the same color of light. The light steering optical element can include at least one microlens, at least one grating, or a combination of both. Separate groups of light emitting elements can be configured and a directional resolution of the light field display can be based on the number of groups. The light field display also includes electronic means configured to drive the light emitting elements in each sub-picture element.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and the benefit of U.S.Provisional Patent Application No. 62/662,629, entitled “ARCHITECTUREFOR LIGHT EMITTING ELEMENTS IN A LIGHT FIELD DISPLAY,” and filed on Apr.25, 2018, the contents of which are incorporated herein by reference intheir entirety.

BACKGROUND OF THE DISCLOSURE

Aspects of the present disclosure generally relate to displays, and morespecifically, to an architecture for light emitting elements in a lightfield display.

With the advent of different video applications and services, there is agrowing interest in the use of displays that can provide an image inthree full dimensions (3D). There are different types of displayscapable of doing so, including volumetric displays, holographicdisplays, integral imaging displays, and compressive light fielddisplays, to name a few. Existing display technologies can have severallimitations, including limitations on the views provided to the viewer,the complexity of the equipment needed to provide the various views, orthe cost associated with making the display.

Light field or lightfield displays, however, present some of the betteroptions as they can be flat displays configured to provide multipleviews at different locations to enable the perception of depth or 3D toa viewer. Light field displays can require a large number of lightemitting elements, at resolutions that can be two to three orders ofmagnitude greater than those of traditional displays. Therefore, thereare challenges in both the number of light emitting elements and themanner in which they are organized that need consideration to enable theultra-high-density required to provide the best possible experience to aviewer.

SUMMARY OF THE DISCLOSURE

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its purpose is to presentsome concepts of one or more aspects in a simplified form as a preludeto the more detailed description that is presented later.

As used in this disclosure, the term sub-raxel may refer to a lightemitting element, including light emitting element that produce a singlecolor of light and light emitting elements that produce red, green, andblue light, the term raxel may refer to a group or allocation ofsub-raxels (e.g., neighboring or nearby positioned sub-raxels), and theterm super-raxel or picture element may refer to an array or arrangementof light emitting elements that are organized, grouped, or otherwiseallocated into different raxels.

In an aspect of the disclosure, a light field display can includemultiple picture elements (e.g., super-raxels), where each pictureelement includes multiple sub-picture elements monolithically integratedon a same semiconductor substrate. A picture element may also bereferred to as a light field picture element. Each sub-picture elementhas a respective light steering optical element and includes an array oflight emitting elements (e.g., sub-raxels) that produce the same colorof light. The light steering optical element can include at least onemicrolens, at least one grating, or a combination of both. Separategroups (e.g., raxels) of light emitting elements can be configured tocompose picture elements (e.g., super-raxels) and a directionalresolution of the light field display can be based on the number ofgroups. The light field display also includes electronic meansconfigured to drive the light emitting elements in each sub-pictureelement.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawings illustrate only some implementation and aretherefore not to be considered limiting of scope.

FIG. 1A illustrates an example of a picture element for light fielddisplays, in accordance with aspects of this disclosure.

FIG. 1B illustrates another example of a picture element for light fielddisplays, in accordance with aspects of this disclosure.

FIG. 2 illustrates an example of light emitting elements in a pictureelement, in accordance with aspects of this disclosure.

FIG. 3 illustrates an example of a light field display having multiplepicture elements, in accordance with aspects of this disclosure.

FIG. 4 illustrates another example of a light field display havingmultiple picture elements, in accordance with aspects of thisdisclosure.

FIG. 5 illustrates an example of a light field display and camera havingmultiple picture elements and light detecting elements, in accordancewith aspects of this disclosure.

FIG. 6A illustrates an example of a cross-sectional view of a portion ofa light field display, in accordance with aspects of this disclosure.

FIG. 6B illustrates another example of a cross-sectional view of aportion of a light field display, in accordance with aspects of thisdisclosure.

FIG. 7A illustrates an example of a configuration of a light fielddisplay, in accordance with aspects of this disclosure.

FIG. 7B illustrates another example of a configuration of a light fielddisplay, in accordance with aspects of this disclosure.

FIG. 8A illustrates an example of an array of light emitting elements ina picture element, in accordance with aspects of this disclosure.

FIG. 8B illustrates an example of a picture element with sub-pictureelements, in accordance with aspects of this disclosure.

FIG. 9A illustrates an example of a picture element with colorconverters, in accordance with aspects of this disclosure.

FIG. 9B illustrates an example of sub-picture elements with colorconverters, in accordance with aspects of this disclosure.

FIG. 9C illustrates another example of sub-picture elements with colorconverters, in accordance with aspects of this disclosure.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known components are shown in blockdiagram form in order to avoid obscuring such concepts.

FIG. 1A shows a diagram 100 a describing an example of a picture elementfor light field displays, also referred to as multi-view displays, forexample. A light field display (see e.g., light field displays 310 inFIGS. 3-5) can include multiple picture elements (see e.g., pictureelements 320 in FIGS. 3-5), which can be organized in arrays, grids, orother types of ordered arrangements. In some implementations, themultiple picture elements can be monolithically integrated on a samesemiconductor substrate. That is, multiple picture elements can befabricated, constructed, and/or formed from one or more layers of thesame or different materials disposed, formed, and/or grown on a single,continuous semiconductor substrate. Additional details regardingmaterials and other aspects related to the semiconductor substrate areprovided below. In this disclosure, the term “picture element” and theterm “super-raxel” can be used interchangeably to describe a similarstructural unit in a light field display. In some instances, a “pictureelement” can be referred to as a pixel, but it is different from a pixelused in traditional displays.

A single picture element can include many light emitting elements 125.As noted above, a picture element is different from a pixel in atraditional display in that a pixel generally identifies a discreteelement that emits light (e.g., in a non-directional manner, Lambertianemission) while a picture element includes multiple light emittingelements 125, which are themselves organized and configured to produceor generate light outputs that can be directional in nature, where theselight outputs (e.g., ray elements) contribute to the formation ofmultiple, different light field views that are to be provided by thelight field display to a viewer in different locations or positions awayfrom the light field display. In an example, each particular location orposition away from the light field display can be associated with alight field view provided by the light field display. Additional aspectsregarding the arrangement and characteristics of the light emittingelements 125 in a picture element are described in more detail below,further identifying differences between a picture element in a lightfield display and a pixel in a traditional display.

A picture element can have a corresponding light steering opticalelement 115 as shown in FIG. 1A. The light steering optical element 115can be configured to steer or direct different ray elements 105 produced(e.g., emitted) by the light emitting elements 125. In an aspect, thedifferent ray elements 105 may correspond to different directions oflight outputs produced by one or more light emitting elements 125. Inthis regard, the directional resolution of the picture element or thelight field display may correspond to a number of light outputdirections supported. Moreover, the light field views provided by thelight field display are produced by a contribution from various lightoutputs that are received by the viewer in a particular location orposition away from the light field display. The light steering opticalelement 115 can be considered part of the picture element, that is, thelight steering optical element 115 is an integral component of thepicture element. The light steering optical element 115 can be alignedand physically coupled or bonded to the light emitting elements 125 ofits respective picture element. In some implementations, there may beone or more layers or materials (e.g., optically transparent layers ormaterials) disposed between the light steering optical element 115 andthe light emitting elements 125 of its respective picture element.

In one example, a light steering optical element 115 can be a microlensor a lenslet as shown in FIG. 1A, which can be configured to steer ordirect the ray elements 105 (e.g., the different light field views) inthe appropriate directions. A light steering optical element 115 caninclude a single optical structure (e.g., a single microlens or lenslet)or can be constructed or formed to include multiple optical structures.For example, a light steering optical element 115 can have at least onemicrolens, at least one grating, or a combination of both. In anotherexample, a light steering optical element 115 can have multiple layersof optical components (e.g., microlenses and/or gratings) that combinedproduce the appropriate light steering effect. For example, a lightsteering optical element 115 can have a first microlens and a secondmicrolens stacked over the first microlens, with the first microlensbeing associated with a first layer and the second microlens beingassociated with a second layer. A different example can use a grating ora grating and microlens combination in either or both layers. Theconstruction of the light steering optical element 115, and thereforethe positioning and characteristics of any microlenses and/or gratingsbuilt or formed therein, is intended to produce the proper steering ordirecting of the ray elements 105.

Different types of devices can be used for the light emitting elements125. In one example, a light emitting element 125 can be alight-emitting diode (LED) made from one or more semiconductormaterials. The LED can be an inorganic LED. To achieve the highdensities needed in light field displays, the LED can be, for example, amicro-LED, also referred to as a microLED, an mLED, or a μLED, which canprovide better performance, including brightness and energy efficiency,than other display technologies such as liquid crystal display (LCD)technology or organic LED (OLED) technology. The terms “light emittingelement,” “light emitter,” or “emitter,” can be used interchangeably inthis disclosure, and can also be used to refer to a microLED. Moreover,any of these terms can be used interchangeably with the term “sub-raxel”to describe a similar structural unit in a light field display.

The light emitting elements 125 of a picture element can bemonolithically integrated on a same semiconductor substrate. That is,the light emitting elements 125 can be fabricated, constructed, and/orformed from one or more layers of the same or different materialsdisposed, formed, and/or grown on a single, continuous semiconductorsubstrate. The semiconductor substrate can include one or more of GaN,GaAs, Al₂O₃, Si, SiC, Ga₂O₃, alloys thereof, or derivatives thereof. Fortheir part, the light emitting elements 125 monolithically integrated onthe same semiconductor substrate can be made at least partially of oneor more of AlN, GaN, InN, AlAs, GaAs, InAs, AlP, GaP, InP, alloysthereof, or derivatives thereof. In some implementations, each of thelight emitting elements 125 can include a quantum well active regionmade from one or more of the materials described above.

The light emitting elements 125 can include different types of lightemitting elements or devices to provide light of different colors, whichin turn enable the light field display to make visually available toviewers a particular color gamut or range. In an example, the lightemitting elements 125 can include a first type of light emitting elementthat produces green (G) light, a second type of light emitting elementthat produces red (R) light, and a third type of light emitting elementthat produces blue (B) light. In another example, the light emittingelements 125 can optionally include a fourth type of light emittingelement that produces white (W) light. In another example, a singlelight emitting element 125 may be configured to produce different colorsof light. Moreover, the lights produced by the light emitting elements125 in a display enable the entire range of colors available on thedisplay, that is, the display's color gamut. The display's color gamutis a function of the wavelength and linewidth of each of the constituentcolor sources (e.g., red, green, blue color sources).

In one implementation, the different types of colors of light can beachieved by changing the composition of one or more materials (e.g.,semiconductor materials) in the light emitting elements or by usingdifferent structures (e.g., quantum dots of different sizes) as part ofor in connection with the light emitting elements. For example, when thelight emitting elements 125 of a picture element are LEDs, a first setof the LEDs in the picture can be made at least in part of InGaN with afirst composition of indium (In), a second set of the LEDs can be madeat least in part of InGaN with a second composition of In different fromthe first composition of In, and a third set of the LEDs can be made atleast in part of InGaN with a third composition of In different from thefirst and second compositions of In.

In another implementation, the different types of colors of light can beachieved by applying different color converters (e.g., colordownconverters) to light emitting elements that produce a same orsimilar color of light. In one implementation, some or all of the lightemitting elements 125 can include a respective color conversion media(e.g., color conversion material or combination of materials). Forexample, each of the light emitting elements 125 in a picture element isconfigured to produce blue light. A first set of the light emittingelements 125 simply provides the blue light, a second set of the lightemitting elements 125 is further configured to downconvert (e.g., usingone conversion media) the blue light to produce and provide green light,and a third set of the light emitting elements 125 is also furtherconfigured to downconvert (e.g., using another conversion media) theblue light this time to produce and provide red light.

The light emitting elements 125 of a picture element can themselves beorganized in arrays, grids, or other types or ordered arrangements justlike picture elements can be organized using different arrangements in alight field display.

Additionally, for each picture element there can be one or more drivers135 for driving or operating the light emitting elements 125. Thedrivers 135 can be electronic circuits or means that are part of abackplane 130 and electronically coupled to the light emitting elements125. The drivers 135 can be configured to provide the appropriatesignals, voltages, and/or currents in order to drive or operate thelight emitting elements 125 (e.g., to select a light emitting element,control settings, control brightness). In some implementations, therecan be a one-to-one correspondence in which one driver 135 can be usedto drive or operate a respective light emitting element 125. In otherimplementations, there can be a one-to-many correspondence in which onedriver 135 can be used to drive or operate multiple light emittingelements 125. For example, the drivers 135 can be in the form of unitcells that are configured to drive a single light emitting element 125or multiple light emitting elements 125.

In addition to the backplane 130 that includes the drivers 135, a lightfield display can also include a plane 120 having the light emittingelements 125. Moreover, a light field display can also include a plane110 having the light steering optical elements 115. In animplementation, two of more of the plane 110, the plane 120, and thebackplane 130 can be integrated or bonded together to form a stacked orthree-dimensional (3D) structure. Additional layers, planes, orstructures (not shown) can also be part of the stacked or 3D structureto facilitate or configure the connectivity, interoperability, adhesion,and/or distance between the planes. As used in this disclosure, the term“plane” and the term “layer” can be used interchangeably.

FIG. 1B shows a diagram 100 b illustrating another example of a pictureelement for light field displays. In this example, the picture elementcan not only provide or emit ray elements 105 (as shown also in FIG.1B), but can also be configured to receive ray elements 107 through thelight steering optical element 115. The ray elements 107 can correspondto directional light inputs that contribute to various views beingreceived by the picture element or the light field display just like theray elements 105 can correspond to directional light outputs thatcontribute to various views being provided by the picture element or thelight field display to a viewer.

In the example in FIG. 1B, a plane 120 a having the light emittingelements 125 can also include one or more light detecting elements 127to receive or capture light associated with the ray elements 107. Theone or more light detecting elements 127 can be positioned in the plane120 a adjacently surrounded by the light emitting elements 125, oralternatively, the one or more light detecting elements 127 can bepositioned in the plane 120 a separate from the light emitting elements125. The terms “light detecting element,” “light detector,” “lightsensor,” or “sensor,” can be used interchangeably in this disclosure.

In some implementations, the light detecting elements 127 can bemonolithically integrated on the same semiconductor substrate as thelight emitting elements 125. As such, the light detecting elements 127can be made of the same types of materials as described above from whichthe light emitting elements 125 can be made. Alternatively, the lightdetecting elements 127 can be made of different materials and/orstructures (e.g., silicon complimentary metal-oxide-semiconductor (CMOS)or variations thereof) from those used to make the light emittingelements 125.

Moreover, a plane 130 a having the drivers 135 can also include one ormore detectors 137 electronically coupled to the light detectingelements 127 and configured to provide the appropriate signals,voltages, and/or currents to operate the light detecting elements 127(e.g., to select a light detecting element, control settings) and toproduce signals (e.g., analog or digital signal) representative of thelight that is received or captured by the light detecting elements 127.

The construction of the light steering optical element 115 in FIG. 1B,and therefore the positioning and characteristics of any microlensesand/or gratings built therein, is intended to produce the right steeringor directing of the ray elements 105 away from the picture element toprovide the various contributions that are needed for a viewer toperceive the light field views, and also to produce the right steeringor directing of the ray elements 107 towards the appropriate lightdetecting elements 127. In some implementations, the light detectingelements 127 may use separate or additional light steering opticalelements than the light steering optical element 115 used in connectionwith the light emitting elements 125. In such cases, the light steeringoptical element for the light detecting elements 127 can be included inthe plane 110 having the light steering optical elements 115.

The different picture element structures described in FIGS. 1A and 1Benable control, placement, and directivity of the ray elements producedby the light emitting elements 125 of the picture element. In addition,the picture element structures in FIG. 1B enable control, placement, anddirectivity of the ray elements received by the picture element.

In FIG. 2, a diagram 200 shows an example of a pattern or mosaic oflight emitting elements 125 in a picture element. In this example, aportion of an array or grid of light emitting elements 125 that are partof a picture element is enlarged to show one of different patterns ormosaics that can be used for the various types of light emittingelements 125. This example shows three (3) different types of lightemitting elements 125, a first type of light emitting element 125 a thatproduces light of one color, a second type of light emitting element 125b that produces light of another color, and a third type of lightemitting element 125 c that produces light of yet another color. Theselight colors can be red light, green light, and blue light, for example.In some implementations, the pattern can include twice as many lightemitting elements that produce red light than those that produce greenlight or blue light. In other implementations, the pattern can include alight emitting element that produces red light that is twice a size ofthose that produce green light or blue light. In other implementations,the pattern can include a fourth type of light emitting element 125 thatproduces light of fourth color, such as white light, for example.Generally, the area of light emitting elements of one color can bevaried relative to the area of light emitting elements of other color(s)to meet particular color gamut and/or power efficiency needs. Thepatterns and colors described in connection with FIG. 2 are provided byway of illustration and not of limitation. A wide range of patternsand/or colors (e.g., to enable a specified color gamut in the display)may be available for the light emitting elements 125 of a pictureelement. In another aspect, additional light emitting elements (of anycolor) can be used in a particular pattern to provide redundancy.

The diagram 200 in FIG. 2 also illustrates having the various types oflight emitting elements 125 (e.g., light emitting elements 125 a, 125 b,and 125 c) monolithically integrated on a same semiconductor substrate.For example, when the different types of light emitting elements 125 arebased on different materials (or different variations or compositions ofthe same material), each of these different materials needs to becompatible with the semiconductor substrate such that the differenttypes of light emitting elements 125 can be monolithically integratedwith the semiconductor substrate. This allows for the ultra-high-densityarrays of light emitting elements 125 (e.g., arrays of RGB lightemitting elements) that are needed for light field displays.

A diagram 300 in FIG. 3 shows a light field display 310 having multiplepicture elements or super-raxels 320. A light field display 310 can beused for different types of applications and its size may varyaccordingly. For example, a light field display 310 can have differentsizes when used as displays for watches, near-eye applications, phones,tablets, laptops, monitors, televisions, and billboards, to name a few.Accordingly, and depending on the application, the picture elements 320in the light field display 310 can be organized into arrays, grids, orother types of ordered arrangements of different sizes. In the exampleshown in FIG. 3, the picture elements 320 can be organized or positionedinto an N×M array, with N being the number of rows of picture elementsin the array and M being the number of columns of picture elements inthe array. An enlarged portion of such an array is shown to the right ofthe light field display 310. For small displays, examples of array sizescan include N≥10 and M≥10 and N≥100 and M≥100, with each picture element320 in the array having itself an array or grid of light emittingelements 125. For larger displays, examples of array sizes can includeN≥500 and M≥500, N≥1,000 and M≥1,000, N≥5,000 and M≥5,000, and N≥10,000and M≥10,000, with each picture element 320 in the array having itselfan array or grid of light emitting elements 125.

In a more specific example, for a 4K light field display in which thepixels in a traditional display are replaced by the picture elements320, the N×M array of picture elements 320 can be a 2,160×3,840 arrayincluding approximately 8.3 million picture elements 320. Depending onthe number of light emitting elements 125 in each of the pictureelements 320, the 4K light field display can have a resolution that isone or two orders of magnitude greater than that of a correspondingtraditional display. When the picture elements or super-raxels 320include as light emitting elements 125 different LEDs that produce red(R) light, green (G) light, and blue (B) light, the 4K light fielddisplay can be said to be made from monolithically integrated RGB LEDsuper-raxels.

Each of the picture elements 320 in the light field display 310,including its corresponding light steering optical element 115 (e.g., anintegral imaging lens), can represent a minimum picture element sizelimited by display resolution. In this regard, an array or grid of lightemitting elements 125 of a picture element 320 can be smaller than thecorresponding light steering optical element 115 for that pictureelement. In practice, however, it is possible for the size of the arrayor grid of light emitting elements 125 of a picture element 320 to besimilar to the size of the corresponding light steering optical element115 (e.g., the diameter of a microlens or lenslet), which in turn issimilar or the same as a pitch 330 between picture elements 320.

An enlarged view of an array of light emitting elements 125 for apicture element 320 is shown to the right of the diagram 300. The arrayof light emitting elements 125 can be a P×Q array, with P being thenumber of rows of light emitting elements 125 in the array and Q beingthe number of columns of light emitting elements 125 in the array.Examples of array sizes can include P≥5 and Q≥5, P≥8 and Q≥8, P≥9 andQ≥9, P≥10 and Q≥10, P≥12 and Q≥12, P≥20 and Q≥20, and P≥25 and Q≥25. Inan example, a P×Q array is a 9×9 array including 81 light emittingelements or sub-raxels 125. The array of light emitting elements 125 forthe picture element 320 need not be limited to square or rectangularshapes and can be based on a hexagonal shape or other shapes as well.

For each picture element 320, the light emitting elements 125 in thearray can include separate and distinct groups of light emittingelements 125 (see e.g., group of light emitting elements 610 in FIGS.6A, 6B, and 8A) that are allocated or grouped (e.g., logically grouped)based on spatial and angular proximity and that are configured toproduce the different light outputs (e.g., directional light outputs)that contribute to produce light field views provided by the light fielddisplay 310 to a viewer. The grouping of sub-raxels or light emittingelements into raxels need not be unique. For example, during assembly ormanufacturing, there can be a mapping of sub-raxels into particularraxels that best optimize the display experience. A similar re-mappingcan be performed by the display once deployed to account for, forexample, aging of various parts or elements of the display, includingvariations in the aging of light emitting elements of different colorsand/or in the aging of light steering optical elements. In thisdisclosure, the term “groups of light emitting elements” and the term“raxel” can be used interchangeably to describe a similar structuralunit in a light field display. The light field views produced by thecontribution of the various groups of light emitting elements or raxelscan be perceived by a viewer as continuous or non-continuous views.

Each of the groups of light emitting elements 125 in the array of lightemitting elements 125 includes light emitting elements that produce atleast three different colors of light (e.g., red light, green light,blue light, and perhaps also white light). In one example, each of thesegroups or raxels includes at least one light emitting element 125 thatproduces red light, one light emitting element 125 that produces greenlight, and one light emitting element 125 that produce blue light. Inanother example, each of these groups or raxels includes two lightemitting elements 125 that produce red light, one light emitting element125 that produces green light, and one light emitting element 125 thatproduces blue light. In yet another example, each of these groups orraxels includes one light emitting element 125 that produces red light,one light emitting element 125 that produces green light, one lightemitting element 125 that produces blue light, and one light emittingelement 125 that produces white light.

Because of the various applications (e.g., different sized light fielddisplays) descried above, the sizes or dimensions of some of thestructural units described in connection with the light field display310 can vary significantly. For example, a size of an array or grid oflight emitting elements 125 (e.g., a diameter, width, or span of thearray or grid) in a picture element 320 can range between about 10microns and about 1,000 microns. That is, a size associated with apicture element or super-raxel 320 can be in this range. The term“about” as used in this disclosure indicates a nominal value or avariation within 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, or 25% from thenominal value.

In another example, a size of each group of light emitting elements 125(e.g., a diameter, width, or span of the group) in a picture element 320can range between about 1 micron and about 10 microns. That is, a sizeassociated with a group of light emitting elements 125 (e.g., raxel 610)can be in this range.

In another example, a size of a group of light emitting elements 125 ina picture element 320 can be greater than 10 microns because a size ofthe light emitting elements 125 in such a group could be as large as 10microns.

In yet another example, a size of each light emitting element 125 (e.g.,a diameter, width, or span of the light emitting element or sub-raxel)can range between about 0.4 microns and about 4 microns. Similarly, asize of each light emitting element 125 (e.g., a diameter, width, orspan of the light emitting element or sub-raxel) can be less than about1 micron. Moreover, a size of each light emitting element 125 in someimplementations can be as large as 10 microns. That is, a sizeassociated with a light emitting element or sub-raxel 125 can be in theranges described above.

In yet another example, a size of a light steering optical element 115(e.g., a diameter, width, or span of a microlens or lenslet) can rangebetween about 10 microns and about 1,000 microns, which is similar tothe range of sizes for a picture element or super-raxel.

In FIG. 4, a diagram 400 shows another example of the light fielddisplay 310 illustrating an enlarged view of a portion of an array ofpicture elements 320 with corresponding light steering optical elements115. The pitch 330 can represent a spacing or distance between pictureelements 320 and can be about a size of the light steering opticalelement 115 (e.g., size of a microlens or lenslet).

In this example, the light field display 310 in FIG. 4 can be a 4K lightfield display with a 2,160×3,840 array of picture elements orsuper-raxels 320. In such a case, for a viewer distance of about 1.5meters or about 5 feet, a size of the light steering optical element 115can be about 0.5 millimeters. Such a size can be consistent with humanacuity of about 1 arc-minute/picture element. The viewer's field of view(FOV) in this example can be about 64 degrees, which can be less than aviewing angle provided by the picture element (e.g., viewing angle>FOV).Moreover, the multiple views provided by the 4K light field display inthis example can have a 4 millimeter width, consistent with a diameterof the human pupil. This can translate to the light steering opticalelement 115 steering the output light produced by a picture element 320having, for example, 31² light emitting elements 125. Accordingly, the4K light field display in this example can provide continuous parallaxwith light field phase or horizontal parallax with light field phase.

A diagram 500 in FIG. 5 illustrates an alternative configuration of alight field display that is also capable of operating as a camera byperforming light field capture using neighboring light detectingelements or sensors 127. In this example, a light field display andcamera 310 a includes an N×M array of picture elements 320, a portion ofthe array is shown enlarged to the right of the diagram 500. The lightdetecting elements 127 can be, for example, silicon-based image sensorsassembled with similar integral optical elements as those used by thepicture elements 320 (e.g., the light steering optical elements 115). Inone implementation, as shown in FIG. 5, the light detecting elements 127can be positioned nearby or adjacent to the picture elements 320 in aone-to-one correspondence (e.g., one capture element for each displayelement). In other implementations, the number of light detectingelements 127 can be less than the number of picture elements 320.

In an example, each light detecting element 127 can include multiplesub-sensors for capturing light in the same fashion as each pictureelement 320 (e.g., a super-raxel) can include multiple light emittingelements 125 (e.g., multiple sub-raxels) or multiple groups of lightemitting elements 125 (e.g., multiple raxels).

As described above in connection with FIG. 1B, the light detectingelements 127 can be integrated in the same plane 120 a as the lightemitting elements 125. Some or all of the features of the lightdetecting elements 127, however, could be implemented in the backplane130 a since the backplane 130 a is also likely to be silicon-based(e.g., a silicon-based substrate). In such a case, at least some of thefeatures of the light detecting elements 127 can be integrated with thedetectors 137 in the backplane 130 a to more efficiently have thecircuitry or electronic means in the detectors 137 operate the lightdetecting elements 127.

A diagram 600 a in FIG. 6A shows a cross-sectional view of a portion ofa light field display (e.g., the light field display 310) to illustratesome of the structural units described in this disclosure. For example,the diagram 600 a shows three adjacent picture elements or super-raxels320 a, each having a corresponding light steering optical element 115.In this example, the light steering optical element 115 can beconsidered separate from the picture element 320 a but in otherinstances the light steering optical element 115 can be considered to bepart of the picture element.

As shown in FIG. 6A, each picture element 320 a includes multiple lightemitting elements 125 (e.g., multiple sub-raxels), where several lightemitting elements 125 (e.g., several sub-raxels) of different types canbe grouped together into the group 610 (e.g., into a raxel) associatedwith a particular light view to be provided by the light field display.A group or raxel can produce various components (see FIG. 6B) thatcontribute to a particular ray element 105 as shown by the right-mostgroup or raxel in the middle picture element 320 a. Is it to beunderstood that the ray elements 105 produced by different groups orraxels in different picture elements can contribute to a view perceivedby viewer away from the light field display.

An additional structural unit described in FIG. 6A is the concept of asub-picture element 620, which represents a grouping of the lightemitting elements 125 of the same type (e.g., produce the same color oflight) of the picture element 320 a. Additional details related tosub-picture elements 620 are described below in connection with FIGS.8B, 9B, and 9C.

A diagram 600 b in FIG. 6B shows another cross-sectional view of aportion of a light field display (e.g., the light field display 310) toillustrate the varying spatial directionality of the ray elementsproduced by three adjacent picture elements or super-raxels 320 a, eachhaving a corresponding light steering optical element 115. In thisexample, a group of light emitting elements 125 in the left-most pictureelement 320 a produces a ray element 105 a (e.g., light output), wherethe ray element 105 a is a combination of ray element components 630(e.g., light output sub-components) produced or generated by the groupof light emitting elements 125. For example, when the group of lightemitting elements 125 includes three light emitting elements 125, eachof these can produce or generate a component (e.g., a light component ofa different color) of the ray element 105 a. The ray element 105 a has acertain, specified spatial directionality, which can be defined based onmultiple angles (e.g., based on two or three angles).

Similarly, a group of light emitting elements 125 in the middle pictureelement 320 a produces a ray element 105 b (e.g., light output), wherethe ray element 105 b is a combination of ray element components 630produced or generated by the group of light emitting elements 125. Theray element 105 b has a certain, specified spatial directionality,different from the one of the ray element 105 a, which can also bedefined based on multiple angles. The same applies for the ray element105 c produced by a group of light emitting elements 125 in theright-most picture element 320 a.

The following figures describe different configurations for a lightfield display (e.g., the light field display 310). In FIG. 7A, a diagram700 a shows a first configuration or approach for a light field display.In this configuration, which can be referred to as a picture elementarray of raxel arrays, different light field views (e.g., View A, ViewB) can be provided by combining the ray elements 105 emitted by thevarious picture elements 320 b in the light field display 310. In thisexample, the light steering optical element 115 can be considered to bepart of the picture elements 320 b. For each picture element 320 b,there is an array or grid 710 of groups of light emitting elements 125(e.g., an array or grid of raxels), where each of these groups producesa light output having at least one component (see FIG. 6B) that isprovided by the light field display 310 as a contribution to constructor form a view perceived by a viewer at a certain location or positionfrom the light field display 310. For example, in each of the pictureelements 320 b, there is at least one group or raxel in the array 710that contributes to View A and there is at least another group or raxelin the array 710 that contributes to View B. In some instances,depending on the location or position of the viewer relative to thelight field display 310, the same group or raxel can contribute to bothView A and View B.

In an aspect of the light field display 310 in FIG. 7A, for each pictureelement 320 b, there can be a spatial (e.g., lateral) offset between aposition of the light steering optical element 115 and a position of thearray 710 based on where the picture element 320 b is positioned in thelight field display 310.

In FIG. 7B, a diagram 700 b shows a second configuration or approach fora light field display that supports light capture as well. The lightfield display and camera 310 a in this configuration is substantiallysimilar to the light field display 310 shown in FIG. 7A, however, in thelight field display and camera 310 a there is a camera lens 725 to steeror direct the ray elements 107 to the appropriate light detectingelements (e.g., sensors 127) in an array 710 a having groups of lightemitting elements 125 along with the light detecting elements.

FIG. 8A shows a diagram 800 a describing various details of oneimplementation of a picture element 320. For example, the pictureelement 320 (e.g., a super-raxel) has a respective light steeringoptical element 115 (shown with a dashed line) and includes an array orgrid 810 of light emitting elements 125 (e.g., sub-raxels)monolithically integrated on a same semiconductor substrate. The lightsteering optical element 115 can be of the same or similar size as thearray 810, or could be slightly larger than the array 810 asillustrated. It is to be understood that some of the sizes illustratedin the figures of this disclosure have been exaggerated for purposes ofillustration and need not be considered to be an exact representation ofactual or relative sizes.

The light emitting elements 125 in the array 810 include different typesof light emitting elements to produce light of different colors and arearranged or configured (e.g., via hardware and/or software) intoseparate groups 610 (e.g., separate raxels), each of which produces adifferent light output (e.g., directional light output) that contributesto one or more light field views perceived by a viewer. That is, eachgroup 610 is configured to contribute to one or more of the views thatare to be provided to a viewer (or viewers) by the light field displaythat includes the picture element 320.

As shown in FIG. 8A, the array 810 has a geometric arrangement to allowadjacent or close placement of two or more picture elements. Thegeometric arrangement can be one of a hexagonal shape (as shown in FIG.8A), a square shape, or a rectangular shape.

Although not shown, the picture element 320 in FIG. 8A can havecorresponding electronic means (e.g., in the backplane 130 in FIG. 1A)that includes multiple driver circuits configured to drive the lightemitting elements 125 in the picture element 230. In the example in FIG.8A, the electronic means can include multiple unit cells configured tocontrol the operation of individual sub-picture elements and/or lightemitting elements that are part of a group.

FIG. 8B shows a diagram 800 b describing various details of anotherimplementation of a picture element 320. For example, the pictureelement 320 (e.g., a super-raxel) in FIG. 8B includes multiplesub-picture elements 620 monolithically integrated on a samesemiconductor substrate. Each sub-picture element 620 has a respectivelight steering optical element 115 (shown with a dashed line) andincludes an array or grid 810 a of light emitting elements 125 (e.g.,sub-raxels) that produce the same color of light. The light steeringoptical element 115 can be of the same or similar size as the array 810a, or could be slightly larger than the array 810 a as illustrated. Forthe picture element 320, the light steering optical element 115 of oneof the sub-picture elements 620 is configured to minimize the chromaticaberration for a color of light produced by the light emitting elements125 in that sub-picture element 620 by optimizing the structure of thelight steering optical element for the specified color wavelength. Byminimizing the chromatic aberration it may be possible to improve thesharpness of the light field views and compensate for how themagnification is different away from the center of a picture element.Moreover, the light steering optical element 115 is aligned and bondedto the array 810 a of the respective sub-picture element 620.

The light emitting elements 125 of the sub-picture elements 620 arearranged into separate groups 610 (e.g., raxels), each of which producesa different one of multiple views. That is, each group 610 is configuredto produce a view (or a contribution to a view) that is to be providedby the light field display that includes the picture element 320. Asillustrated by FIG. 8B, each group 610 includes collocated lightemitting elements 125 from each of the sub-picture elements 620 (e.g.,same position in each sub-picture element).

As shown in FIG. 8B, the array 810 a has a geometric arrangement toallow adjacent placement of two or more sub-picture elements. Thegeometric arrangement can be one of a hexagonal shape (as shown in FIG.8B), a square shape, or a rectangular shape.

Although not shown, the picture element 320 in FIG. 8B can havecorresponding electronic means (e.g., in the backplane 130 in FIG. 1A)that includes multiple driver circuits configured to drive the lightemitting elements 125 in the picture element 230. In some examples, oneor more common driver circuits can be used for each of the sub-pictureelements 620. In the example in FIG. 8B, the electronic means caninclude multiple unit cells configured to control the operation ofindividual sub-picture elements and/or light emitting elements that arepart of a sub-picture element.

A diagram 900 a in FIG. 9A shows an example of the picture element 320in FIG. 8A where the light emitting elements 125 produce lights ofdifferent colors by means of respective, individual optical convertersor color conversion media for each of the light emitting elements 125.

In one example, there can be a first converter means (e.g., opticalconverters 910 a) to convert light produced by a first set of the lightemitting elements 125 to blue light, a second converter means (e.g.,optical converters 910 b) to convert light produced by a second set ofthe light emitting elements 125 to green light, and a third convertermeans (e.g., optical converters 910 c) to convert light produced by athird set of the light emitting elements 125 to red light.

In another example, the first set of the light emitting elements 125 canproduce blue light and therefore the first converter means (e.g.,optical converters 910 a) is not needed (e.g., the first converter meansis optional).

A diagram 900 b in FIG. 9B shows an example of the picture element 320in FIG. 8B where the light emitting elements 125 in each of thesub-picture elements 620 produce light of the same color by means ofrespective, individual optical converters or color conversion media foreach of the light emitting elements 125.

In one example, there can be a first converter means (e.g., opticalconverters 910 a) to convert light produced by the light emittingelements 125 of a first one of the sub-picture elements 620 to bluelight, a second converter means (e.g., optical converters 910 b) toconvert light produced by the light emitting elements 125 of a secondone of the sub-picture elements 620 to green light, and a thirdconverter means (e.g., optical converters 910 c) to convert lightproduced by the light emitting elements 125 of a third one of thesub-picture elements 620 to red light.

In another example, the light emitting elements 125 of the first one ofthe sub-picture elements 620 can produce blue light and therefore thefirst converter means (e.g., optical converters 910 a) is not needed(e.g., the first converter means is optional).

A diagram 900 c in FIG. 9C shows another example of the picture element320 in FIG. 8B where the light emitting elements 125 in each of thesub-picture elements 620 produce light of the same color by means of arespective, single optical converter or color conversion media for eachof the sub-picture elements 620.

In one example, there can be a single, first converter means (e.g.,optical converter 910 a) to convert light produced by all of the lightemitting elements 125 of a first one of the sub-picture elements 620 toblue light, a single, second converter means (e.g., optical converter910 b) to convert light produced by all the light emitting elements 125of a second one of the sub-picture elements 620 to green light, and asingle, third converter means (e.g., optical converter 910 c) to convertlight produced by all of the light emitting elements 125 of a third oneof the sub-picture elements 620 to red light.

In another example, the light emitting elements 125 of the first one ofthe sub-picture elements 620 can produce blue light and therefore thesingle, first converter means (e.g., optical converters 910 a) is notneeded (e.g., the first converter means is optional).

For the FIGS. 9A-9C, each of the first converter means, the secondconverter means, and the third converter means can include a compositionhaving phosphorous to produce the color conversion. For example,different compositions of phosphorous can be used to produce the variouscolor conversions. Alternatively or additionally, each of the firstconverter means, the second converter means, and the third convertermeans includes quantum dots. The quantum dots for the first convertermeans can have a first size, the quantum dots for the second convertermeans can have a second size, and the quantum dots for the thirdconverter means can have a third size, where the size of the quantumdots affects or controls the wavelength of the light to produce thecolor conversion.

Although the present disclosure has been provided in accordance with theimplementations shown, one of ordinary skill in the art will readilyrecognize that there could be variations to the embodiments and thosevariations would be within the scope of the present disclosure.Accordingly, many modifications may be made by one of ordinary skill inthe art without departing from the scope of the appended claims.

What is claimed is:
 1. A light field display, comprising: multiplepicture elements, each picture element including multiple sub-pictureelements monolithically integrated on a same semiconductor substrate,each sub-picture element having a respective light steering opticalelement and including an array of light emitting elements that producethe same color of light; and electronic means configured to drive thelight emitting elements in each sub-picture element.
 2. The light fielddisplay of claim 1, wherein the light steering optical element isaligned and bonded to the array of light emitting elements of therespective sub-picture element.
 3. The light field display of claim 1,wherein the light steering optical element includes at least onemicrolens, at least one grating, or a combination of both.
 4. The lightfield display of claim 1, wherein for each picture element the lightemitting elements of different sub-picture elements produce differentcolors of light.
 5. The light field display of claim 1, wherein for eachpicture element the light steering optical element of one of thesub-picture elements is configured to optimize the chromatic dispersionfor a color of light produced by the light emitting elements in thatsub-picture element.
 6. The light field display of claim 1, wherein eachlight emitting element in the array of light emitting elements is alight emitting diode (LED).
 7. The light filed display of claim 6,wherein the LED is an inorganic LED.
 8. The light field display of claim1, wherein: the light emitting elements in the array of light emittingelements for a first sub-picture element of the sub-picture elementsinclude a first set of LEDs that produce red light, the light emittingelements in the array of light emitting elements for a secondsub-picture element of the sub-picture elements include a second set ofLEDs that produce green light, and the light emitting elements in thearray of light emitting elements for a third sub-picture element of thesub-picture elements include a third set of LEDs that produce bluelight.
 9. The light field display of claim 8, wherein: the first set ofLEDs includes LEDs made at least in part of InGaN with a firstcomposition of In, the second set of LEDs includes LEDs made at least inpart of InGaN with a second composition of In different from the firstcomposition of In, and the third set of LEDs includes LEDs made at leastin part of InGaN with a third composition of In different from the firstand second compositions of In.
 10. The light field display of claim 1,wherein: the light emitting elements in the array of light emittingelements for a first sub-picture element of the sub-picture elementsproduce blue light, the light emitting elements in the array of lightemitting elements for a second sub-picture element of the sub-pictureelements are configured to downconvert blue light to produce greenlight, and the light emitting elements in the array of light emittingelements for a third sub-picture element of the sub-picture elements areconfigured to downconvert blue light to produce red light.
 11. The lightfield display of claim 1, wherein the light emitting elements in each ofthe sub-picture elements produces a same color of light, furthercomprising: a first converter means to convert light produced by thelight emitting elements of a first sub-picture element of thesub-picture elements to blue light; a second converter means to convertlight produced by the light emitting elements of second firstsub-picture element of the sub-picture elements to green light; and athird converter means to convert light produced by the light emittingelements of a third sub-picture element of the sub-picture elements tored light.
 12. The light field display of claim 11, wherein each of thefirst converter means, the second converter means, and the thirdconverter means includes a composition having phosphorous.
 13. The lightfield display of claim 11, wherein each of the first converter means,the second converter means, and the third converter means includesquantum dots.
 14. The light field display of claim 13, wherein thequantum dots for the first converter means have a first size, thequantum dots for the second converter means have a second size, and thequantum dots for the third converter means have a third size.
 15. Thelight field display of claim 1, wherein the semiconductor substrateincludes one or more of GaN, GaAs, Al₂O₃, Si, SiC, Ga₂O₃, alloysthereof, or derivatives thereof.
 16. The light field display of claim 1,wherein the light emitting elements in the array of light emittingelements are at least partially made of one or more of AlN, GaN, InN,AlAs, GaAs, InAs, AlP, GaP, InP, alloys thereof, or derivatives thereof.17. The light field display of claim 1, wherein the array of lightemitting elements in each sub-picture element has a geometricarrangement to allow adjacent placement of two or more of thesub-picture elements.
 18. The light field display of claim 13, whereinthe geometric arrangement is one of a hexagonal shape, a square shape,or a rectangular shape.
 19. The light field display of claim 1, wherein:separate groups of light emitting elements are configured from the lightemitting elements in each of the arrays of the sub-picture elements, andeach group of light emitting elements produces an optical output havingspatial directionality.
 20. The light field display of claim 19, whereinthe optical output of each group of light emitting elements includescomponents generated by the individual light emitting elements in thegroup.
 21. The light field display of claim 20, wherein each of thecomponents of the optical output corresponds to a light of a differentcolor.
 22. The light field display of claim 1, wherein: separate groupsof light emitting elements are configured from the light emittingelements in each of the arrays of the sub-picture elements, and adirectional resolution of the light field display is based on a numberof the separate groups.
 23. The light field display of claim 22, whereineach group of light emitting elements includes collocated light emittingelements from each of the sub-picture elements, non-collocated lightemitting elements from each of the sub-picture elements, or acombination thereof.
 24. The light field display of claim 22, whereineach group of light emitting elements includes light emitting elementsthat produce at least three different colors of light.
 25. The lightfield display of claim 24, wherein the light emitting elements in eachgroup of light emitting elements that produce at least three differentcolors of light include light emitting elements that produce red light,light emitting elements that produce green light, and light emittingelements that produce blue light.
 26. The light field display of claim24, wherein the light emitting elements in each group of light emittingelements that produce at least three different colors of light includetwo light emitting elements that produce red light, one light emittingelement that produces green light, and one light emitting element thatproduces blue light.
 27. The light field display of claim 24, whereinthe light emitting elements in each group of light emitting elementsthat produce at least three different colors of light include one lightemitting element that produces red light, one light emitting elementthat produces green light, one light emitting element that produces bluelight, and one light emitting element that produces white light.
 28. Thelight field display of claim 1, wherein a size of each of thesub-picture elements is between about 10 microns and about 1,000microns.
 29. The light field display of claim 1, wherein a size of eachlight emitting is between about 0.4 microns and about 4 microns.
 30. Thelight field display of claim 1, wherein a size of each light emittingelement is less than about 1 micron.
 31. The light field display ofclaim 1, wherein a size of the light steering optical element is about asize of one of the sub-picture elements.
 32. The light field display ofclaim 1, wherein: the picture elements are constructed on a first layer,the electronic means is constructed on a second layer, and the firstlayer is positioned over the second layer and integrated with the secondlayer.
 33. The light field display of claim 1, wherein the pictureelements are arranged in a grid-like pattern.
 34. The light fielddisplay of claim 33, wherein the grid-like pattern is an N×M array ofpicture elements, and wherein N>100 and M>100.
 35. The light fielddisplay of claim 34, wherein N>1000 and M>1000.
 36. The light fielddisplay of claim 1, wherein the electronic means includes multipledriver circuits, the multiple driver circuits configured to individuallydrive each of the light emitting elements in the respective sub-pictureelement.
 37. The light field display of claim 1, wherein the electronicmeans includes multiple driver circuits, the multiple driver circuitsbeing configured to drive the light emitting elements in each of thesub-picture elements.
 38. The light field display of claim 1, whereinthe sub-picture elements in any of the picture elements aremonolithically integrated on the semiconductor substrate.
 39. The lightfield display of claim 1, wherein the picture elements aremonolithically integrated on the semiconductor substrate.